In the processing of sheet materials, i.e. webs, bands, individual sheets or piece goods, the material frequently requires processing by a tool or other device which must be accurately positioned relative to the path of the web. Typical of such processing is the slitting of a continuous web utilizing blades which must be accurately positioned transversely of the web travel direction. Other processing devices likewise may have to be accurately positioned in a web processing apparatus relative to the web travel direction or in the web travel direction.
The specific case of a machine for this purpose is a machine which may be required for cutting or other processing of paper or cardboard webs and which may have a number of elements or devices which must be accurately positioned in accordance with the format or size of the sheets to be processed or produced.
Pairs of circular blades, for example, may be used to cut such a web and must be accurately positioned relative to one another and with respect to the format of the product to be made. Such blades are typical of the devices which are to be accurately positioned by the apparatus of the present invention and serve to subdivide the web into individual webs by longitudinally slitting or even for subdividing webs into sheets or pieces.
In the case in which a relatively wide web of material must be longitudinally slit into a number of narrower webs continuously, the cutting devices must be accurately positioned transversely of the web travel direction.
In German patent document DE-AS 21 42 117, a cutting apparatus for this purpose is described in which the pairs of circular blades are carried on respective slides displaceable on guides, e.g. rails, transverse to the web travel direction by respective endless belts which can be driven by electric motors and to which the slides are respectively clamped. The belt is constituted as the drive element. Each blade slide is provided, therefore, with an arresting member having two positions. In one position the member brings about engagement with a stretch of the belt and in another position, the member brings about engagement with the guide to lock the guide in place. The arresting member can be a double-acting piston.
In this system, the slides can only be coupled to one stretch or pass of the respective belt so that, for reversal of the movement of the slide, the drive of the belt must be reversed. This requires a complex and expensive control system for the belt drive and increases the time required for changeover of the position of the blades in a multislide system since it is not possible to simultaneously adjust the positions of all of the slides of a key belt if the blade carts or slides are required to be moved in opposite directions for this adjustment.